Die for cutting screw-threads



(No Model.)

N E MARTIN DIE FOR CUTTING SCREW THREADS No. 543,136.. Patented July 23, 1895.

59 Z XW UNITED STATES PATENT OFFICE.

NATHAN E. MARTIN, OF GREENFIELD, MASSACHUSETTS.

DIE FOR CUTTING SCREW-THREADS.

SPECIFICATION forming part of Letters Patent No. 543,136, dated July 23, 1895.

Application filed October 30, 1894:. Serial No. 527,469. (No model.)

To all whom it may concern.-

. Be it known that I, NATHAN E. MARTIN, a citizen of the'United States of America, resid: ing at, Greenfield, in the county of Franklin and State of Massachusetts, have invented certain new and useful Improvements in Dies for Cutting Screw-Threads, of which the following is a specification.

My invention relates to improvements in dies for cutting screw-threads; and the object of the invention is to improve the holding and adjusting means for holding the die or cutting sections within the collet, whereby ghelidsaid cutting-sections will be more firmly The invention is illustrated in the accompanying drawings, in which- Figure 1 is an elevation of the die; Fig. 2, a cross-section. Fig. 3 is a rear view of one of the die-sections. Figs. 4 and 5 are views of the screws;

In the drawings the collet or holder for the die sections is designated at A and is of substantially the ordinary or any desired form, having an open face or side a for the insertion of the die-sections and an inwardly-extending flange a upon its other face, against which the die-sections bear.

The die-sections indicated at B and B are duplicates .of each other and are also of the ordinary or any desired form,except as hereinafter specified. The abutting ends b b of the sections are beveled, thus providing a V- shaped space or groove between the said ends, and a set-screw 0 passes through the wall of the collet and its conical front enters the V- shaped groove. By means of these conical screws located upon opposite sides of the collet a limited adjustment is permitted to the die-sections. The end faces of the die-sections, forming the walls of the V shaped grooves, converge toward the rear, so that the pressure from the conical points of the screws upon these converging walls will tend to keep the die-sectionsforced tightlyagainst the flange of the collet and will thus hold them securely within the collet and against any fore referred to is accomplished by the coniresponding bearing-surfaces in the die-sections, as at 6. These grooves or depressions are preferably inclined rearwardly, and the screws bearing against their sloping bottoms assist in forcing the die-sections toward the flange of the collet and holding it firmly in place.

Having thus described my'invention, what I claim is I 1. In combination with a collet having a lateral bearing flange, die sections contained within the same, the opposing ends of said sections having a double inclinenamely, an incline extending from the inner faces of the sections to the outer faces and an incline extending from the front faces rearwardly to the flange, and conical screws passing through the wall of the collet and contacting with the opposing ends of the die sections, said screws by reason of the double inclines serving to adjust the parts and to hold them in place, substantially as described.

2. The combination with the collet having the bearing flange, of the die sections having their abutting end faces converging toward said flange and having inclined grooves in their peripheral faces, the conical screwsextending between the conical end faces, and the bearing screws impinging against the inclined bottoms of the grooves, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

NATHAN E. MARTIN. Witnesses:

FRANCIS E. MARTIN, J. P. S. OTTERSON. 

